Improvement in ventilating-caps for pipes, chimneys



F. GREAVES VENTILATING CAPS Fon PIPES, cHIMNEYs, sw.

Patented Se-pt.5,1876.

N.1a1,9se.

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N.PET= RS, PHoTq-LITHQGRAPMER. WASHINGTONy D f -UNITED STATES PATENTFFICE.

FRANKGREAVES, on BROOKLYN, NEW'YORK.

IMPROVEMENT IN VENTlLATlNG-CAPS FOR PIPES, CHIMNEIVSI, &c.

Specication forming part of Letters Patent No. 181,936, dated September5, 1876 application led -November 12, 1873.

i To all whom it may concern:

Be it known that I, FRANK GREAvEs, of the city of Brooklyn, in thecounty of Kings and State of New York, have invented certain new anduseful Improvements in Ventilator- Caps for Flues, Pipes, Ste.; and I dohereby declare that the following is a full, clear, and exactdescription thereof, and of its mode or manner of operation, referencebeing had to the accompanying drawings, and to the letters of referencemarked thereon, and making a part of this specification.

The nature of my invention consists in the production of an improvedventilator cap or head for ues and pipes or chimneys, which will securea constant upward draft through such ue, pipe, Ste., and preven't eitherupward or downward currents of air passing into and down such ue orpipe, to thereby inter- 'fere with or overcome the draft, and which canbe used with complete success on ues or pipes standing by the side of,or terminating below the top-of, walls, 8vo., and near their base. Y

Figure l is a perspective view of my improved ventilator-cap with itssecondary top, and Fig. 2 is a vertical cross-section of the same. Fig.3 is a perspective view ot' the same cap with the secondary top removed,and Fig. et is a' vertical cross-section of the same,

A is a tube, which is put over or fitted tightly upon the iiue or pipe,and which should project some little distance-say, four to liveinches-above the top, in the case of an eightinch flue or pipe. Coveringsuch tube is a shield or deecting-cap, B, which is supported bystandards b b so as to be about four inches above the top of such tube,and whi'ch is some- I what larger than the open end of the tube, so

l C, leaving an open space between the two of from three to four inches,which extends downward some four or tive inches below the top ot' theinner tube, and also extends upward in a straight line to about the lineofthe periphery or edge of the delecting-cap B, when it contracts inwardor toward the center, and extends in such direction far enough to makeits mouth C about the same size as the inner tube A. In the case of adownward current or blast oi' air, the contracted mouth C limits thequantity of air that can enter, and the deilecting-cap B, being largerthan the top of the tube A, not only prevents such a blast entering intoand passing down'theilue or pipe, but, in fact, causes such downwardcurrent to increase the draft of the Hue, as the air passes down and outof the opening d, carrying the smoke, 85o., down with it through suchopening. Any upward current or blast of air outside of the flue isforced by means of the rim a` against the side ofthe outer tube C, whichthus passes up and' mouth C of the outer tubeC should also be vsubstantially as large as the tube A, so as to permit unobstructed andfree discharge of the products of combustion and air rwithout anytendency to backward movements of the same. The shield or cap B shouldalso project over the sides ofthe tube A only sufcie'ntlyfar to preventany downward current or blast entering such tube A, and the particularconstruction, as described, of the under side of such cap, so as to haveno cavity or open space under it in or bywhich there can be any eddyingor back action of the air or products of combustion, and so as to deectoutward the upward current, is also regarded as highly advantageous andessential to the full satisfactory action of the device.

When the ventilator is to be used in positions where the natural draftis interfered with by cross-currents or eddies of air, as near highWalls, or when the lue opens or terminates near the bottom of such aWall, I make use of a secondary cap, D, which is placed a littledistance above the mouth C', and Which has a breadth about the same asthe diameter or horizon tal Width of the outer tube C. Such secondarycap more eft'ectually prevents any down- Ward current interfering withor overcoming vthe draft, and has been proved by actual eX- periment toovercome the injurious effects produced by such Walls, creating orcausing doWnward and cross currents of air, which, in most cases,seriously interfere With, if they do not practically render useless,ordinary ventilating-caps.

1. The inner tube A, outer or overlapping tube G, and deiiecting-cap B,With rim pro jecting over the lend of the tube A, combined With theangular deiiector a, substantially as F. GREAVES.

Witnesses:

S. D. LAW, A. T. GURLITZ.

